Hex Head Cap Screw System of Measurement Inch Basic Material Steel Material Grade Grade 5 Fastener Finish Zinc Plated Dia./Thread Size 5/16 In.-18 Fastener Length 2 1/2 in Fastener Thread Direction Right Hand Fastener Thread Type UNC (Coarse) Fastener Thread Style Partially Threaded Fastener Industry Standards ASME B18.2.1 Head Type Hex Min Thread Length 7/8 in Head Height 13/64 in Head Width 1/2 in Package Quantity 50